Winder tension control



y 1969 E. M. LA POINTE 3,442,463

WINDER TENSION CONTROL Filed Nov. 5, 1965 Sheet 01"4 INVENTOR. Edward M. LoPoinre ATTORNZY y 6, 1969 E. M. LA POINTE 3,442,463

WINDER TENS ION CONTROL Filed Nov. 5, 1965 Sheet 2 of 4 TENSILE +25 25 STRENGTH CLUTCH TORQUE +20 20 g +|5 l5 1 g was T SION 2 O +|o IO 5 Z a E +5 5 Lu O 8 LENGTH g woum) WINDAGE a FRICTION TORQUE Fig. 2

WEB TORQUE CLUTCH TORQUE +|5 IS A (I) m d 2 2 +|o IO 9 Lg- I) 2 LL] TENSION (8 LBS.) +5

RTIAL TORQUE O 900 IOOO LENGTH WOUND TORQUE IN IN. LBS.

WINDAGE 8T -5 FRICTION TORQUE WEB TORQUE INVENTOR. Edward M. LoPoinre ATTORNEY RAKING TORQUE May 6, 1969 E. M. LA POINTE 3,442,463

WINDER TENSION CONTROL Filed Nov. 3, 1965 INVENTOR. Edward M. LoPoime BY ATTORN V y 6, 1969 E. M. LA POINTE 3,442,463

WINDER TENSION CONTROL Filed Nov. 5, 1965 Sheet 4 of 4 m a n m 6 as I as x 59 7| 69 INPUT g ml Is OUTPUT 5? E 58 Ill WIN INVENTOR. Edward M. LuPoin're ATTOR NEY United States Patent US. Cl. 242-64 8 Claims ABSTRACT OF THE DISCLOSURE Web winding apparatus is disclosed for winding webs with a predetermined tension profile. A principal feature of the invention disclosed is the modification of the torque transmitting ability of a winder clutch in accordance with a predetermined clutch torque counteracting program during the progress of the wind from start to finish. This feature permits webs to be wound either with constant tension throughout the wind or with any desired tension profile through the wind. Clutch torque counteracting means are disclosed for achieving the above-described feature of the web winding apparatus of the invention, which means are responsive to the progress of a wind on a mandrel and act on the mandrel so as to decreasingly counteract the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind. In one embodiment of the apparatus of the invention, the clutch torque counteracting means disclosed include braking means acting upon the mandrel and program cam means operably connected-to the braking means to control application of braking force by the brake means to the mandrel, the cam means being actuated by means responsive to the progress of a web wind.

This invention relates to winding apparatus and more particularly to apparatus for winding lightweight webs, or tapes, at high speeds.

It is common practice in the production of low-cost roll items, such as toilet tissue, to employ high speed equipment in which the rolls are wound on a series of movable mandrels which are successively brought into winding position to commence a winding operation immediately after the completion of the preceding winding operation and without stopping or slowing the incoming web of material. Attempts are constantly made to operate winders of this type at increasingly higher speeds in order to render the operation more economical. Although elaborate control systems have been developed through the years, -high speed operations of such machines have always been replete with problems of web breakage, particularly when winding low strength materials, such as paper.

Obviously, web breaks occur during winding when the tension to which the web is subjected exceeds the tensile strength of the web material. In high speed winding machines it is difiicult to sense the tension existing in the web during the wind, primarily because of space limitations within the machine. More commonly, a clutch is imposed between the drive and the winding mandrel to limit the amount of torque imparted to the mandrel and thereby indirectly limit the tension to which the web is subjected. The use of such a clutch offers the further advantage of permitting the mandrel to slow down during the wind as the roll grows so that the web can be wound at constant speed while the mandrel is driven from a constant speed drive. An automatic winding machine incorporating these features is disclosed in US. Patent No. 2,769,600 to Kwitek et al.

It is the principal object of this invention to improve the operation of the aforementioned type of winding ice equipment so that the winding operation may be performed at higher speeds and/or with less frequent web breakage.

I have discovered by investigation and analysis that machines equipped with clutches for driving the winding mandrels subject the web to large variations in tension during the course of the wind. I have further discovered that these extreme variations of tension in the web' are the result of the mac-hines failure to take into account and compensate for the various torque conditions existing during the wind. In particular, such machines, in the past, have disregarded or failed properly to take into account the combination of the inertial torque caused by deceleration of the winding mandrel and the wound web during the wind as well as the changing radius or moment arm of the roll being wound.

It is, therefore, another object of this invention to provide means for counteracting the torque transmitting ability of a winding clutch to vary the applied torque in inverse ratio to the varying inertial torque present in the winding system such as to oppose the inertia and high web tension tending to occur when the roll is of small radius.

It is well known that if any degree of uniformity is to be maintained in the tension of the wound roll in a center drive winding operation it is necessary to increase the torque applied to the winding mandrel as the roll of material grows to offset the increasing moment arm through which the torque acts on the web being wound. In various prior art machines centrifugal force responsive clutch elements have been employed to progressively increase the torque imparted to the winding mandrel during the web Wind. See, for example, US. Patent No. 2,901,192 to Nystrand. The use of a centrifugal clutch for this purpose has a number of drawbacks and limitations. The principal deficiencies are that the use of such a clutch does not produce the precise torque program required and is limited to the particular operating speed for which the clutch is designed. Any departure from the design speed results in the clutch transmitting more or less torque than is desired for winding at constant web tension.

It is a further object of this invention to provide a means for counteracting the torque imparting ability of a winder clutch in a predetermined programmed manner to increase its torque imparting ability progressively as more web material is wound and the size of the wound roll grows. This program can, in accordance with this invention, also take into consideration other factors affecting Web tension during the wind, such as torque conditions resulting from friction and windage in the system.

The principal feature, then, of this invention resides in modifying the torque transmitting ability of a winder clutch in accordance with a predetermined clutch torque counteracting program during the progress of the wind from start to finish. This feature of the invention permits webs to be wound either with constant tension throughout the wind or with any desired tension profile through the Wind.

It is a further object of this invention to improve the reliability of winders employing a clutch by reducing the tendency for the clutch to undergo excessive slip prior to commencement of a web wind. In prior machines such slippage resulted in the winding surface of the mandrel not being brought up to web speed at the time the web Was transferred to the mandrel and the transfer could not be accomplished smoothly. This object is achieved by designing into the programming means portion of the clutch torque counteracting means the ability to transmit substantially a maximum clutch torque to prevent slippage prior to web transfer.

These and other objects, advantages and features of the 3 invention can be better understood from the following detailed description of the invention wherein reference is made to the accompanying drawings, in which:

FIGURE 1 is a diagrammatic sectional view taken near one end of a winding machine of a type to which this invention is applicable;

FIGURE 2 is a graphic illustration of various torque effects present and tension forces experienced by the web during a wind on a typical prior art machine operating at the upper limit of its operating speed;

FIGURE 3 is a graphic illustration similar to FIGURE 2 illustrating conditions experienced in a winding machine incorporating this invention and operating at a comparable speed;

FIGURE 4 is a sectional view through a clutch for one of the mandrels of the machine illustrated in FIGURE 1;

FIGURE 5 is a schematic view in perspective of a clutch torque counteracting means and associated programming means;

FIGURE 6 is an elevation view of programming means with portions broken away to illustrate operation of a valve;

FIGURE 7 is a sectional view of the fluid pressure distributor assembly taken along the axis of a winder turret support shaft shown in FIGURE 4;

FIGURE 8 is an elevation view of a clutch torque counteracting means controllable by the programming means of FIGURE 6.

FIGURE 1 illustrates a typical continuous winding machine employing a plurality of winding mandrels 11 rotatably carried by the arms of a turret 12 which, in turn, is rotatably supported by a shaft 13. Suitable means (not shown) are provided for rotativel-y indexing turret 12 in a clockwise direction for bringing succeeding mandrels 11 into winding position adjacent a rotatably mounted bed roll 14 over which a web 15 to be wound is fed. The web 15 may be directed to bed roll 14 through perforator rolls indicated at 16 and 17 and a feed roll 18. During normal operation bed roll 14 is driven at a substantially constant velocity and as a roll of web material is completed on one of the mandrels 11 that mandrel is moved away from the bed roll and the succeeding mandrel is indexed into position near the bed roll, the web is severed and the leading edge of the severed web is transferred to a succeeding mandrel by suitable means, such as the retractable knife indicated at 19.

In order to insure a smooth transition of web feed from one mandrel 11 to the next mandrel and to insure continuous feed of the web 15 during the wind it is essential that each mandrel as it approaches the winding position be rotatably driven to bring its Winding surface up to the surface speed of bed roll 14 and subsequently, during the wind, be permitted to slow down to compensate for the growth of the roll being wound on the mandrel. The drive means illustrated in FIGURE 1 is similar to that disclosed in the aforementioned Patent 2,769,600 and includes a moving flexible belt 21 positioned to engage a clutch mechanism 22 carried by each of the mandrels 11. It will be noted that drive belt 21 engages a clutch 22 only when the mandrel for that clutch is approaching bed roll 14 or is in the vicinity thereof during the web wind. Belt 21 may be driven by any suitable means, such as the pulley and belt drive 23, and a drive motor 24. The other moving components of the winder, such as turret 12 and bed roll 14 may also be driven from motor 24, but if driven by other motive sources their movements should be synchronized so that drive belt 21 is moving at a linear speed which will cause the surface velocity of a driven mandrel 11 to match the surface velocity of bed roll 14.

Winding machines such as that illustrated in FIG- URE 1 often have incorporated therein slip clutches which permit the winding mandrel 11 to slow down during the web wind, notwithstanding the fact that drive belt 21 is propelled at a constant linear velocity. So called, constant 4 torque clutches of this type limit the maximum amount of torque transmitted to their winder mandrels and are supposed to prevent the web from being subjected to excessive tension during the wind. In reality such clutches are ineffective to compensate for all factors influencing web tension and at higher winding speeds are totally ineffective to prevent web breakage.

Winding conditions FIGURE 2 illustrates what has been determined by laboratory investigation and analysis to be typical torque conditions and web tension conditions existing during the winding of a series of rolls of toilet tissue or a log of such tissue in a winder employing constant torque clutches. The line identified as Clutch Torque represents the torque which is actually transferred through the clutch 22 and applied to the winding mandrel 11. For reasons which need not be discussed here there is a slight drop in the torque applied to the mandrel by the clutch at the beginning of the web wind. For all practical purposes, however, the torque transmitted is essentially constant throughout the wind. It will be noted that the web tension changes considerably during the web wind and is highest at the beginning of the wind (see curve labeled Web Tension). In the particular illustration of FIG- URE 2 the tension in the web at the beginning of the wind approaches 20 pounds, which is near the 20 to 30 pounds tensile strength possessed by a perforated web of tissue paper for winding 20 rolls of toilet tissue. Consequently, any slight malfunction of the machine or nonuniformity of thickness or strength of the web can result in breaking the web at or shortly after the beginning of a wind.

FIGURE 2 also illustrates one of the factors which contribute to high web tension at the beginning of a wind with existing winding equipment. Note the form of the curve identified as Inertial Torque. This torque acts in the direction of rotation of the rotating mandrel and is the result of deceleration of the mass of the mandrel and the web being progressively wound thereon. It will be noted that the inertial torque is greatest at the begin ning of the web wind when the mandrel is turning at very high rotative speed and is undergoing its maximum deceleration.

The ordinary clutch is not capable of compensating for inertial torque during the wind. This is particularly true as winding speeds are increased because of the marked effect the higher speeds have on increasing initial inertial torque. This accounts for the experience with prior machines that as higher operating speeds are attempted more frequent breakage of the web material is encountered.

FIGURE 2 further illustrates the other torque factors which have been determined to be present in the winding of weak webs at high speeds. The line identified as Windage and Friction Torque illustrates the magnitude of the effect mandrel friction and windage have in tending to slow the mandrel and the web wound thereon. The winding system is held in equilibrium by the web torque, which simply is that troque which is imposed on the rotating mandrel by tension in the web and wich equals the algebraic sum of the clutch torque and the inertial torque, less the windage and friction torque.

FIGURE 3 illustrates graphically the more favorable winding conditions which can be practiced utilizing the present invention. It will be noted that in this example the tension is held substantially constant at approximately 8 lbs. from the beginning to the end of the wind. In this instance, the clutch torque is maintained substantially constant and it will be noted that this clutch torque profile is substantially the same as the clutch torque profile of the prior machines represented by FIGURE 2. However, it will be noted that the web torque follows a smoothly increasing curve in the negative direction as is desirable to wind a web on a growing roll at constant tension.

To produce a constant tension wind as indicated in FIGURE 3 at about a positive eight pounds, a clutch torque counteracting means is programmed to provide a braking torque as indicated by the smoothly decreasing curve in the negative direction.

The web wind conditions illustrated graphically in FIG- URE 3 can be reproduced in accordance with this invention by means of a clutch in combination with a programmed clutch torque counteracting means which supplies a braking torque to controllably counteract the inherent torque imparting ability of the clutch in accordance with the progress of the wind. A preferred embodiment of this clutch is illustrated in FIGURE 4 and is identified generally by reference numeral 22. There is one such clutch 22 for each winding mandrel 11 and each clutch is carried by its mandrel preferably in a location between spiders 26 and 27 of the turret 12. Spider 26 has securely clamped thereon a sleeve 28 within which mandrel 11 is free to turn in a bearing 29. An extension of sleeve 28 has rotatably mounted thereon a drive wheel, or pulley 31. Pulley 31 is mounted on bearings 32 which enable the pulley to rotate freely on sleeve 28 and independently of mandrel 11. Pulley 31 is equipped with a V-shaped channel 33 for engagement with drive belt 21 (see FIG. 1). One end of pulley 31 has a flange extension providing a clutch face 34 which constitutes a friction surface of the clutch.

Keyed to mandrel 11 for rotation therewith is an elongated sleeve 42. Sleeve 42 carries for rotation therewith a slidably mounted clutch ring 38 which has embedded in one face thereof a circular array of friction pads 36 positioned to engage clutch face 34. Friction pads 36 are urged against clutch face 34 by an array of compression springs 43 bearing on the back face of clutch ring 38 and carried in recesses in the face of a hub 44. Hub 44 is mounted for rotation with sleeve 42 but is movable axially thereon for the purpose of varying the compression of springs 43.

A cylindrical sleeve 45 is concentrically disposed about mandrel sleeve 42 and is keyed both axially and circumferentially to sleeve 42. Sleeve 45 has threads 46 cut into its outside cylindrical surface. A cylindrical actuating sleeve 47 is concentrically disposed about mandrel sleeve 42 and threadedly mounted at one end to sleeve 45 by means of threads 46. Sleeve 47 is connected at its other end to hub 44 by means of a bearing 48.

As illustrated by FIGURE 4, the relative torque transmitting ability of each winding clutch may be separately adjusted by rotation of its respective cylindrical actuating sleeve 47 in the desired direction upon threads 46 of axially fixed sleeve 45 resulting in axial movement of hub 44. This changes the compression of clutch springs 43 to vary the elfectiveness of these springs in biasing friction pads 36 into engagement with clutch face 34. When viewed from the right hand end of mandrel 11 as shown in FIGURE 4, clockwise movement of sleeve 47 increases the compression of springs 43 and coutnerclockwise rotation of sleeve 47 decreases the compression of springs 43.

The rotation of cylindrical actuating sleeve 47 is effected by an operator to obtain a desired clutch torque curve as illustrated in FIGURE 3. The provision of separate adjustment means on each mandrel 11 shown in FIG- URE 1 allows the adjustment of the torque profile of the clutch 22 to higher or lower limits to enable an operator to compensate for factors such as clutch Wear and spring strength which may be dilferent for each clutch 22 on a winder. Clutch adjustment may also be desirable when Web products having a different tensile strength are being Wound on the winder or to select a more tightly wound or a more loosely wound roll in order to maintain a predetermined roll size when winding webs of different bulk.

It should be evident from the earlier discussion of FIG- URE 2 that there are certain torque conditions acting on the winding system which are not taken into account by a clutch so as to provide a relatively constant web tension profile. There are, for example, the effects of friction torque and the requirement for increasing torque as the roll grows during winding. In accordance with this invention there is superimposed upon the winding mandrel a program control which counteracts the torque imparted by the clutch in accordance with the progress of the wind, i.e., length of web wound. The program control accounts for the other variable torque conditions to enable the clutch to impart to the mandrel the constantly changing torque required to wind the web at constant tension. This programmed clutch torque counteracting means includes a cylindrical brake drum 51 concentrically disposed about elongated sleeve 42 and keyed thereto for rotation therewith. A brake shoe 52 is urged into frictional engagement with the drum 51 to a greater or lesser degree to controllably counteract the torque of mandrel 11 imparted by the clutch. The action of brake shoe 52 is controlled by programming apparatus illustrated schematically by FIGURE 5 and shown in detail in FIGURES 6, 7 and 8.

Referring now to FIGURE 5, brake shoe 52 is shown in frictional contact with brake drum 51. A programming cam 53 is arranged to be driven by the shaft of bed roll 14 shown in FIGURE 1 which may be connected to cam 53 'by means of a speed reducing gear train 93. In this manner, the rotation of cam 53 may be synchronized with the rotation of bed roll 14 of the paper machine so as to be responsive to the progress of a web wind. Cam 53 is shaped so as to impart greater or lesser pressure to brake shoe 52 in order to controllably counteract the torque-imparting ability of the clutch 22 and to thereby allow the desired torque to be imparted to mandrel 11 in accordance with the progress of the winding of a roll. In this manner, by properly shaping cam 53, a relatively constant web tension may 'be achieved.

Cam 53 actuates an air pressure regulator 54, the output of which is transmitted to an actuating air cylinder 55 through a rotary air distributor 56. By these means, air from an air supply is regulated within air pressure regulator 54 and the regulated pressure is transmitted to an actuating air cylinder 55 associated with a respective mandrel 11 mounted upon the winder. As the winder turret is rotatably indexed to a new position, a regulated air pressure is transmitted through rotary air distributor 56 to the respective air cylinder 55 associated with the next succeeding mandrel 11. Air cylinder 55 is arranged to apply pressure in a controlled manner to brake shoe 52 to controllably urge the brake shoe 52 into frictional contact with brake drum 51 in a responsive programmed manner.

With the above brief description of the entire programming means of the invention and its relation to the winding apparatus, the details of the above means will now be described in greater detail with reference to FIG- URES 6, 7 and 8.

FIGURE 6 illustrates an air supply pressure regulator 54 having an input 57 through which air pressure from an air pressure source (not shown) is transmitted and an output 58 through which regulated air pressure is transmitted to rotary air distributor 56. The air pressure in output 58 is indicated on a pressure meter 59 which connects to output line 58 within pressure regulator 54.

A thrust member 61 is reciprocably mounted through one wall of regulator 54 and bears against one end of a coiled spring 60 located therein. The opposite end of spring 60 bears against a seat 62 secured to the center of a diaphragm '63. Seat 62 has a hole 64 through its center shaped so as to seat a needle valve tip 65 of a valve member 66. Valve member 66 has an annular seat 67 which bears against the rim surrounding hole 68 due to pressure from compressed spring 69.

Input 57 enters a chamber 71 and, when pressure increases in output 58 is desired, diaphragm 63 depresses valve member 66 from seat around hole 68 allowing increased fluid pressure to flow into a chamber 72 and hence through outlet 58. Valve member 66 is depressed by pressure of seat 62 against needle valve tip 65 in response to programming cam 53. When reduced pressure is desired as indicated by upward movement of diaphragm 63 in response to programming cam 53, needle valve tip 65 withdraws from hole 64 allowing air to escape from chamber 72 through seat 62 and pass through a hole 73 in the casing of regulator 54.

A lever member 76 is rotatably carried by pivot pin 77 at a point intermediate its ends and secured to a support frame 78 carrying pressure regulator 54. One end 79 of lever member 76 is constantly urged against the outermost end of thrust member 61 by means of a spring cage assembly indicated generally by reference numeral 81. Assembly 81 comprises a spring 82 compressibly disposed between end 79 of lever member 76 and the head 83 of a bolt 84 threadedly mounted in a bracket 85 attached to frame 78. A lock nut 86 is arranged to bear against the bottom of bracket 85 to maintain the position of bolt 84. This provides a means of adjusting the pressure of spring 82 on the end 79 of lever member 76.

A programming cam 53 is arranged to bear against the opposite end '87 of lever member 76 in order to controllably counteract the biasing force imparted to a lever member 76 by the spring cage assembly 81. This controls the axial movement of thrust member 61 and, correspondingly, the air pressure within regulator 54 in accordance with the predetermined shape of the cam 53.

A preferred form of cam means for this purpose is illustrated in FIGURE 6 and takes the form of a large circular cam 53 which is supported for rotation about its axis by a pin 88. Referring briefly to cam 53 itself, it will be seen that the cam has a program surface segment 79 adapted to counteract the torque of clutch 22 in a desired manner during the progress of a wind. It also has a high-rise dwell segment 90 ahead of program segment 89 which is adapted to effect the application of the full torque of clutch 22 to the mandrel which is moving into winding position to insure that the mandrel is being brought up to initial winding velocity. The torque imparting ability of the clutch 22 is severely curtailed just prior to transfer of the web end to the mandrel by means of the shelf 92 in the cam surface. Relative movement of cam 53 with respect to bed roll 14 is effected by means of a gear train 93 as described in FIGURE which synchronizes the rotation of cam 53 with the amount of web material wound on the mandrel. In this manner, cam 53 is driven at a rate which relates to the operating speed of the paper machine and the winder and the progress of a web wind.

FIGURE 7 shows a rotary air distributor 56 which enables air pressure transmitted through the output of pressure regulator 54 to be fed to successive air cylinders operating in conjunction with mandrels upon a winder as the turret 12 of the winder is rotationally indexed into position relative to bed roll 14. Air pressure from regulator 54 is received at input 94 and transmitted through a stationary port plate 95 to one of a plurality of ports 96 in a rotating port plate 97. The ports 96 in rotating port plate 97 connect through passageways 98 in shaft 13 to radially extending feed lines 99 which terminate at individual actuating air cylinders 55.

Input 94 terminates in stationary port plate 95 in a peripheral slot cut into the face of plate 95 so that a particular port 96 in rotating port plate 97 is connected to the pressure regulator 54 during a portion of the arc path of the turret 12. The slot is aligned with the path of a port 96 in plate 97 and is sufficiently long to enable operation on the mandrel at the start of indexing to bring it up to proper transfer speed and also after indexing to continue to control the mandrel torque during the wind.

FIGURE 8 illustrates in greater detail the arrangement of radial feed pipes 99 and their connection to actuating air cylinders 55. Each air cylinder 55 is fixedly secured to the turret assembly 12 and has a piston 101 reciprocably disposed within a cylindrical pressure chamber 102 and arranged for axial movement. One end of piston 101 is pinned to one end of a lever member 103 which is pivotably attached to spider 26 at its opposite end by pin 100. Lever member 103 carries a brake shoe 52 retained within a holder 104 which is bolted to the center of lever member 103. By this arrangement, air transmitted to one of the feed lines 97 through rotating port plate 97 is fed into its respective air cylinder 55. The relative pressure exerted by air cylinder 55 is proportional to the pressure of the air fed into it and, correspondingly,.the frictional force exerted by brake shoe 52 against brake drum 51 is regulated in this manner.

Operation of clutch and clutch torque counteracting means When the machine is in operation, the turret 12 will index one of the mandrels 11 into winding position to receive the leading edge of a web being fed over bed roll 14. As the mandrel approaches winding position, the groove 33 of the clutch pulley 31 engages drive belt 21. Belt 21 is moving at a velocity which rotates clutch pulley 31 at an angular velocity which matches the surface velocity of the mandrel 11 to the velocity of the web leaving bed roll 14. During this prewind period it is highly desirable that there be no slippage in the clutch 22 so that the mandrel 11 positively assumes the desired angular velocity. This condition is assured by virtue of the brake shoe 52 being subjected to no pressure by actuating air cylinder 55 by virtue of the follower end 87 of lever member 76 being in engagement with the high rise dwell segment of the program cam 53. The lack of frictional counteracting torque being applied to the mandrel 11 insures that the mandrel will be driven at a matched surface velocity with the web leaving bed roll 14 since full driving torque will be applied through clutch 22.

As the mandrel 11 reaches its winding position and web 15 is transferred to the mandrel to start the wind, follower end 87 of lever member 76 moves into the program segment 89 of cam 53 after dropping over the shelf 92 in the program cam surface. This causes thrust member 61 to increase the pressure applied to actuating air cylinder 55 thereby applying a large frictional torque to mandrel 11 which tends to strongly counteract the torque of clutch 22 at that point in time. As can be observed from the clutch torque curve in FIGURE 3, the torque transferred to the mandrel through clutch 22 is quite low at the beginning of the wind. At this point the inertial torque of the clutch and mandrel substantially assist in winding the web 15 onto the mandrel with very little, if any, additional torque being required.

As the wind progresses and the roll of web material on the mandrel increases in size, the inertial torque decreases rapidly because of slowing of the mandrel velocity. Simultaneously, as the wind progresses and the roll diameter increases, additional torque must be transmitted to the mandrel 11 by the clutch 22 to compensate for the growing moment arm through which mandrel torque is applied to the web 15.

During this period a decreasing amount of counteracting torque is applied to the clutch 22 by a slow decrease in the pressure applied to brake shoe 52 as controlled by cam 53. The clutch torque counteracting ability of the brake shoe 52 and the brake drum 51 is decreased in a programmed manner by virtue of the follower end 87 following the progressively increasing radius of program segment 89 of cam 53. The torque transmitting, or imparting, ability of clutch 22 is thus caused to follow the general profile indicated by the clutch torque curve in FIGURE 3 by the programmed change of compression of brake shoe 52 under control of program cam 53.

At the end of the wind web 15 is severed by the knife 19 in bed roll 14 and the mandrel 11 containing the completed roll is indexed by turret 12 out of winding position as the succeeding mandrel is brought into position. Clutch 22 of the mandrel containing the wound roll is thus moved out of engagement with drive belt 21 and thismandrel is allowed to stop so that the roll wound thereon can be removed.

From the foregoing it should be apparent that this invention provides novel means for improving the performance of high speed winding'machines. This ability of pro- 'gramming systems constructed in accordance with this invention to controllably counteract clutch torque applied to winding mandrels and thereby maintain a uniform tension in the web being wound is of particular significance in winding weak webs, such as perforated toilet tissue, which may be caused to break by even slight variations in the winding tension.

Moreover, it should be apparent that this invention is useful in winding applications wherein a tension profile during the wind is desired which is something other than constant tension. For example, in winding high gloss films it is desirable to wind the inner layers of the roll more tightly than the outer layers in order to prevent slippage of the inner layers during the latter part of the wind. For such applications, it is possible to alter the shape, or profile, of the program segment 59 of cam 56 so as to counteract the clutch torque and obtain the desired torque transfer profile.

While the invention has been described with reference to particular embodiments thereof it is understood that changes and modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In web winding apparatus, a rotatable mandrel on which a web is to be wound, drive means, a clutch for transmitting torque from said drive means to said mandrel, and clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind.

2. In apparatus for winding webs at constant velocity and with a predetermined tension profile, a rotatable mandrel on which the web is to be wound, a turret supporting said mandrel and adapted to move the mandrel into winding position, constant speed drive means, clutch means driven by said drive means and capable of transmitting a varying torque to said mandrel, means for adjusting the torque transmitting ability of said clutch means, and clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counter-acting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind.

3. In apparatus for winding webs at constant velocity and with a predetermined tension profile, a rotatable mandrel on which the web is to be wound, constant speed drive means, a clutch driven by said drive means and capable of transmit-ting a varying torque to said mandrel, said clutch including at least two friction members and means biasing said members into frictional engagement, means for adjusting said biasing means and, correspondingly, the torque transmitting ability of said clutch, and clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind.

4. In web winding apparatus, a rotatable mandrel on which a web is to be wound, drive means, a clutch for transmitting torque from said drive means to said mandrel, and clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind, said means including braking means acting upon said mandrel and program cam means operably connected to said brake means to control application of braking force by said brake means to said mandrel, and means responsive to the progress of a web wind for actuating said cam means.

5. In web winding apparatus wherein a rotatable mandrel on which a web is to be wound is driven by a drive means operably connected to said mandrel through a clutch capable of transmitting a varying torque to said mandrel, the improvement comprising clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind, said means including brake means acting upon said mandrel and adapted to retard the rotation of said mandrel, cam means operably connected to said brake means to control the application of braking force by said brake means to said mandrel, and means responsive to the progress of a web wind for actuating said cam means.

6. In web winding apparatus having a plurality of rotatably mounted mandrel, turret means supporting said mandrels and adapted to successively index said mandrels into winding position, drive means, means carried by each of said mandrels and adapted to be driven by said drive means when its mandrel is in winding position, clutch means carried by each of said mandrels capable of imparting varying torque to the mandrels from said drive means, and*clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind, said means being adapted to counteract the torque imparting ability of the clutch at a low level as the mandrel approaches winding position to insure rotation of the mandrel at a velocity comparable to the velocity of said drive means, to counteract the torque imparting ability of the clutch at a higher level as a web is transferred to the mandrel for winding, and to subsequently progressively decreasingly counteract the torque imparting ability of the clutch during a web wind.

7. In web winding apparatus comprising a bed roll over which a web is fed at constant speed, a series of r0- tatable mandrels on which the web is to be wound, constant speed drive means for rotating said mandrels as the latter are successively brought into winding position near said bed roll, said drive means being capable of rotating said mandrels with a winding surface velocity substantially equal to the surface velocity of said bed roll, clutch means carried by each of said mandrels for transmitting torque to the mandrels from said drive means, and clutch torque counteracting means responsive to the progress of a wind on said mandrel and acting on said mandrel for decreasingly counteracting the torque transmitted to the mandrel by the clutch in a programmed manner during the web wind, said counteracting means including brake means acting upon said mandrel and adapted to retard the rotation of said mandrel, cam means operably connected to said brake means to control the application of braking force by said brake means to said mandrel, and means operably connecting said cam means to said bed roll for actuating said cam in response to the progress of a web wind.

8. In web winding apparatus comprising a bed roll over which a web is fed at constant speed, a series of rotatable mandrels on which the web is to be wound, and a constant speed drive means for rotating said mandrels as the latter are successively brought into winding position near said bed roll, said drive means being capable of rotating said mandrels with a winding surface velocity substantially equal to the surface velocity of said bed roll, the combination therewith of clutch means carried by each of said mandrels for transmitting torque to the mandrels from said drive means, said means including a braking means operably connected to said mandrel and adapted to exert a varying retarding force upon said mandrel, cam means operably connected to said brake means to control the ap-' plication of braking force by said brake means to said mandrel in a predetermined manner, and means operably connecting said cam means to said bed roll for actuating said cam in response to the progress of a web wind, said cam means being adapted to counteract the torque imparting ability of the clutch at a low level as the mandrel approaches winding position to insure rotation of the mandrel at a velocity comparable to the velocity of said drive means, to counteract the torque imparting ability of the clutch at a higher level as a web is transferred to the mandrel for winding, and to subsequently progressively decreasingly counteract the torque imparting ability of the clutch during a web wind.

References Cited UNITED STATES PATENTS 1,331,584 2/1920 Rosenfeld 242-675 2,608,355 8/1952 Bell et a1 24245 2,769,600 11/1956 'Kwitek et a1 242-64 X 2,828,926 4/ 1958 Phelps 242--64 X 10 2,978,200 4/ 1961 Larson et a1 242-75 .51

WILLIAM S. BURDEN, Primary Examiner. 

